Mitsubishi laser TV

It's hardly a compliment to be called a lightweight, except if you happen to be a 62-inch rear-projection 1080p laser TV.

Consumer electronics giant Mitsubishi now hopes to combine the inherently large size of a rear-projection unit into a sleeker, lighter-weight product and pack it with enough advanced technology to out-dazzle the rest of the HD pack, although consumers may have to wait a while to see this next-gen version of DLP for themselves.

Since last winter, Mitsubishi has been trickling out details of what it unofficially is calling "Laser TV," citing it as a breakthrough in existing DLP (digital light processing) that it believes will eventually move HDTV one step further to perfection cosmetically and technologically, through the use of colored lasers.

DLP, a registered trademark of Texas Instruments, traditionally uses white-light mercury bulbs. Mitsubishi's new system, instead, uses separate red, green and blue semiconductor lasers in combination with an HD chip, which those who have seen a real-world demo (mostly dealers and Mitsubishi employees) say provides richer and more complex colors and hues, and noticeably more distinct HD clarity and depth-of-field.

Mitsubishi contends that lasers also prompt a more realistic manifestation of "black" than current DLP, plasma, LCD or CRT screens. Lasers purportedly shut off totally when not needed, frame-to-frame, creating a more natural blackness. (In contrast, today's DLP mercury bulbs do not completely blink off, according to Mit-subishi.) Today's DLP units without colored lasers already produce at least 16 million color variations, including 124,000 shades of gray, according to TI.

SOPHISTICATED LIGHT

The key component of non-laser DLP technology is an optical semiconductor (a Digital Micromirror Device or "DLP chip"), invented by TI nearly 20 years ago. It has called the chip "probably the world's most sophisticated light switch," with up to two-million hinge-mounted microscopic mirrors less than one-fifth the width of a human hair.

When the DLP chip is synchronized with a digital video signal, light source and projection lens, its flexible mirrors reflect digital images to a screen. The microscopic mirrors can reflex (blink on and off) a few thousand times per second. Much of TI's proprietary technology will be used with Mitsubishi's Laser TV, but source lighting from mercury bulbs will be replaced by the lasers.
It appears there is only one working Laser TV screen in existence for demo purposes for now; Mitsubishi is hesitant to show it off at trade shows because it still lacks suitable cabinetry and other non-technical aesthetics. A non-working cosmetic sample (see photo) of a 62-inch unit--along with the sole working screen demo--were featured at Mitsubishi's annual line show for dealers at its Huntington Beach, Calif., headquarters in April.

"We did display a working sample that was not in a finished cabinet [to] prove that we could produce a good HD picture in a finished cabinet using our laser technology," said Marty Zanfino, director of product development at Mitsubishi. Zanfino said the 62-inch diagonal screen will boast a depth of only about 10 inches and not require very much framing around the screen because advanced plastics will replace glass components in the rear projector, making the large unit lighter. (Plastics have replaced heavier glass casings in some current DLP products, as well.)
Consequently, he said, today's typical heavy-duty screen frames will not be necessary, and may be no wider than an eighth of an inch. The lighter overall weight will allow for a lower center of gravity; nearly the entire frontage can be devoted to screen surface. Thus, the Laser TV units will occupy a more compact footprint and allow sleeker cosmetic designs that could set the product apart from the rest.

But HDTV is usually about the picture--not weight or even design--and Mitsubishi is confident this is where Laser TV will excel.

"The color gamut is significantly larger because the lasers are so intense," Zanfino said. He compares its optimum video quality as being equal or superior to 35mm film. Zanfino said although prices will not be announced until the product is released, when asked, he acknowledged that Laser TV probably will start off somewhat higher-priced than today's DLP and plasma units: "We'll see, but lasers cost more than mercury bulbs."

Advantages

One major claim of laser advocates is the ability to produce undiluted, perfect colors allowing precise hue mixing. With the color enhancement capable with lasers, up to 90% of the visible spectrum can be displayed.Other improvements that laser advocates claim are bulbs that will never blow out, and increased efficiency by using two-thirds less power than traditional rear projection televisions. Historically, however, lasers have been too bulky and expensive for widespread adoption.
The laser technology advocates claim that the technology will allow displays with a richer, more vibrant color palette than the conventional plasma, LCD or CRT displays.

They also claim the displays will:

be half the weight and cost of Plasma or LCD displays
require around 25% of the power required by Plasma or LCD displays
be very thin like Plasma and LCD displays are today
have a very wide colour gamut
have a 50,000 hour life
maintain full power output for the lifespan of the laser, resulting in a picture that doesn't progressively degrade over time, such as with plasma and LCD technology

Drawbacks

Together with the advantages of laser sources, there are reports that also describe some of the current shortcomings of laser displays,[18] such as the following:
Safety. The high power emitted by the coherent laser sources is inherently dangerous to human vision. Proponents claim that integrating the devices with the needed diffusion filters removes this risk.

Speckle. Due to the narrowband coherent light source, speckle will be an issue at the display. This has also been a problem in laser lighting displays and has been solved through modulation of the light source thus widening the bandwidth and reducing the possibility for coherent interference. Proponents claim that this issue can be minimized by the use of diffusing elements and multiple sources. These, however, may impact display resolution and system cost.